Figures 4A-a, b, c, d, e and 4f clearly demonstrate that NOX4 is seldom expressed in normal urothelium, nor is it expressed in reactive atypia (mostly due to chronic inflammation/denudation), but was overexpressed in low or high-grade and non-invasive or invasive urothelial carcinoma cells, including carcinoma in situ (CIS). This evidence concerns the gene NOX4 and in situ carcinoma.